ESA's mission to de-clutter low-Earth orbit takes a step forward

A graphic depicting the distribution of orbital debris around Earth(Credit: ESA)

ESA's mission to
mitigate the environmental impacts on low-Earth orbit from mankind's
relentless march into space has entered a new phase, ahead of its
make-or-break review before the ESA's Council of Ministers in
December 2016. The e.Deorbit program would launch multiple debris-seeking probes into orbit each year, tasked with the removal of
defunct satellites and other potentially hazardous man-made objects
from low-Earth orbit.

Currently, there is
still very little chance of two satellites colliding. However, as we
increase our presence in space those odds will inevitably go up, and
when such a collision does occur, it has the potential to create a
catastrophic chain reaction.

This was the case back
in 2009 when a collision between satellites Iridium 33 and
Kosmos-2251 created a cloud of smaller debris that lead to a
collision warning for the ISS only last year. If it hadn't been for
the presence of ESA's ATV Georges Lemaître, which succeeded in
pushing the station out of harm's way, the debris could have damaged
the station, and possibly even led to a loss of life.

Accidents such as this,
and unchecked proliferation of man-made debris, could eventually
result in low-Earth orbit becoming all but unusable. This scenario is
known as the Kessler syndrome.

Steps are already being
taken to avoid this eventuality. For example, newly manufactured
satellites must operate with a contingency to put them out of harm's
way at the end of their operational lives, either by pushing
themselves into a seldom-used graveyard orbit, or simply by
de-orbiting themselves.

However pre-existing
derelict satellites and the upper stages of launch vehicles represent
a significant problem, one that 2.Deorbit hopes to tackle.
Officially, the project has moved from Phase-A to Phase-B1, which is
ESA's way of saying that it is now in the process of getting the
satellite design finished up and ready for production.

"I am very pleased
with the progress we are making," states project manager for
e.Deorbit, Robin Biesbroek. "In this phase we will
really go into detail on the concept of operations, e.Deorbit’s
subsystems design, and especially the capture and deorbit phases."

The design for the
satellite is currently far from finalized, and the agency and its
partners have yet to decide on just how the probe will grapple with,
and dispose of, potentially harmful chunks of debris. This said, ESA
has announced its intent to use the upper stage of a Vega rocket as
the platform for the satellite, and has now ruled out using a
harpoon-based system to capture the space junk. This leaves snaring
the debris via a weighted net, or grabbing it with a robotic arm as
the remaining options for the final design.